VALERIA CETORELLI is Research Officer at the London School of Economics and Political Science and Postdoctoral Fellow at the Johns Hopkins Bloomberg School of Public Health. ISAAC SASSON is Assistant Professor of Sociology at Tel Aviv University. NAZAR SHABILA is Assistant Professor of Public Health at Hawler Medical University. GILBERT BURNHAM is Professor of International Health at the Johns Hopkins Bloomberg School of Public Health.

On August 3, 2014, the Islamic State (or ISIS) attacked the region around Mount Sinjar in northwestern Iraq, near the country’s border with Syria. The region was home to approximately 400,000 Yazidis[1], the members of an ancient and often-persecuted religious minority whose beliefs and practices incorporate elements of Christianity, Islam, and other monotheistic religions. ISIS seized Sinjar City and the surrounding villages in a few hours, kidnapping and killing the Yazidis who could not flee. Those who could escaped to Mount Sinjar[2], where they were besieged by ISIS for days, enduring temperatures of over 122 degrees Fahrenheit without access to water, food, or medical care. At the request of the Iraqi government, the United States began conducting air strikes and air-dropping humanitarian aid on August 8. Between August 9 and August 13, Kurdish forces opened a safe corridor, allowing most of the surviving Yazidis to flee through Syria into the Kurdistan region of Iraq.

It has now been a year since a UN Independent International Commission of Inquiry determined that ISIS’ violence against the Yazidis constitutes a case of genocide[3], defined by the 1948 Convention on the Prevention and Punishment of the Crime of Genocide as “acts committed with intent to destroy, in whole or in part, a national, ethnical, racial or religious group.” ISIS had openly proclaimed, in its English-language magazine, Dabiq, its intent to destroy the “pagan” Yazidi minority through killing, enslavement, and forced conversion.

But although ISIS’ genocidal intent has long been clear, the extent of the group’s atrocities has remained murky. Local authorities and human rights organizations have made some attempts to compile lists of victims. According to those lists, between 2,500 and 5,000 Yazidis had been killed by ISIS while over 6,000 had been kidnapped. But the UN has not yet been able to independently verify these figures.

Despite the difficulties involved, it is important to document the extent of ISIS’ genocidal violence against the Yazidis. Such documentation provides information for humanitarian assistance and protection, aids rescue missions and health-care strategies, supports accountability in national